1. Field of the Invention
This invention relates to steel wools and more particularly, to a material for steel wool which is imparted with excellent ability of being machined.
2. Description of the Prior Art
In general, steel wools are fabricated through a processing step in which a steel wire is continuously machined in a depth of several microns along the length of the wire by the use of a tool having a specific shape of groove, thus presenting various problems. That is, the problems involved are:
(1) A steel wool is not obtained continuously by machining and dust and broken pieces are formed in large amounts by breakage, causing the yield and workability to lower;
(2) The life of the tool becomes short because of the machining of steel wire, e.g. an ordinary life of 3 to 4 hours is reduced to less than 2 hours; and
(3) The tool life abruptly reduces when the machining speed is increased.
We have made extensive studies on the problems involved in the fabrication of steel wool and, as a result, found that these problems are chiefly caused by nonmetallic inclusions and particularly Al.sub.2 O.sub.3 present in the steel wire. In order to fabricate a steel wool which is uniform and continuous without breakage of chips and also to reduce the wearing-out of a machining tool, it is necessary that not only components contained in the steel wool should properly be determined with their controlled contents, but also Al.sub.2 O.sub.3 as a nonmetallic inclusion should be regulated in amounts.